Mutational landscapes of HNF MODY gene products display a wide distribution with functional implications

Hepatocyte nuclear factors (HNFs) play an essential role in the development and function of vital organs such as the liver, kidney, intestine, and pancreas by regulating the expression of multiple genes involved in organ development, nutrient transport, and diverse metabolic pathways. Among them, HNF1α, HNF1β, and HNF4α play critical roles in glucose-stimulated insulin secretion in pancreatic β-cells and are monogenic causes of diabetes referred to as maturity-onset diabetes of the young (MODY). Numerous mutations have been identified in MODY patients, and the numbers are growing. MODY mutations disrupt protein structure/function in specific ways, and deciphering the exact molecular mechanisms of their mutational effects is vital for better understanding their molecular function and potential therapeutic intervention. This article compiles the updated overall landscapes of missense mutations in members of these transcription factors. We show that mutations are widely but unevenly distributed in their sequence and molecular structures and infer their functional implications. We map the variants to several hotspot residues. While some mutations have been previously characterized, we find that significant proportions of them remain to be mechanistically defined. Because these proteins represent ideal targets to improve β-cell function and survival, we discuss the status and prospects for therapeutic intervention.